Palmer's third Senate seat in doubt as senator-elect says no formal deal with Ricky Muir

The Palmer United Party's influence in the Senate has been thrown into doubt, with its WA Senate seat in doubt and a senator-elect describing the deal with the Motoring Enthusiast Party as merely a "gentleman's handshake".

Earlier this month the PUP signed a Memorandum of Understanding with MEP senator-elect Ricky Muir, forming a powerful voting bloc of four when the new Senate sits in July next year.

But today Tasmanian PUP senator-elect Jacqui Lambie said her party and Mr Muir would "watch each other's back" but that their votes were not in automatic lock-step.

"There's no deal - it's just a gentlemen's handshake to know that we're supporting each other when we possibly can," she told a press conference in Hobart.

"We don't want Ricky Muir up there being eaten alive by these politicians.

"We're lucky, we're a really tight team, so we didn't want him floating around there and being put round the wrong direction."

Mr Palmer announced the voting alliance with Mr Muir in a press conference in Brisbane nearly three weeks ago, but has refused to release the text of their agreement.

The party founder was not at today's press conference in Hobart, but Ms Lambie was accompanied by Queensland senator-elect Glenn Lazarus.

Western Australia Senate spot in doubt, question over 'informal' votes